When I got my Toshiba 65 H84 CRT-RPTV 2 years ago, I tried out an HDMI cable. HDMI cables were more expensive then than they are now. I decided to use component and if I could see any difference with the component cables I would switch back to the HDMI. Still using the component cables.

HDMI cables can be had pretty cheaply now, (the name of the place that sells cables very reasonably escapes me right now, however, someone else can probably come up with the name).

I think that if I was planning on migrating to HD DVD I would get an inexpensive HDMI cable.

I've never been able to detect a difference between the HDMI and component connections on my JVC LCoS from either of my DVD players or my HD-DVR. I now run component video along with the digital audio from all sources through my a/v receiver. I get the switching convenience without any discernable loss in video quality.

Also remember that "Component Video" is an umbrella term that is used usually to define color-opponent space in which luma and chroma are defined, rather than RGB. Note that Analog Component video (YPbPr) is what most people mean when they say "component video" but componenet video also exists digitally, and can be transmitted by HDMI (YCbCr), in addition to RGB. DVI is spec'd for RGB only, however some devices also can send component via DVI, although it is not standard.